New pcb m4 symbols:

PKG_SOT23OWN
PKG_TO92OWN
PKG_TO220STANDOWN

could be used with gschem footprint attribute with or without additional
parameter for the pinnames. The parameter is simply the pinname list in
order of defined pins which I catch from the datasheet. So if you
want to use the footprint with different pinout simply call it with

PKG_SOT23OWN BCE

if you want pin1 is B, pin 2 is C and pin 3 is E.
